There has been conventionally known an electrophotographic type printer to which a developing device is detachably attached. The developing device includes a casing, a developing roller supported by the casing and bearing toner thereon, and a layer thickness regulating member that regulates thickness of a layer of toner formed on a surface of the developing roller.
There has been proposed, as such a developing device, a developing device having a configuration in which the layer thickness regulating member includes a thin plate spring having substantially a flat-plate shape, a chip which is made of a rubber member and provided at a free end portion of the thin plate spring, and a pair of seal members which are provided on a pair of longitudinal ends of the thin plate spring so as to be disposed adjacent to the chip in the longitudinal direction.
In the developing device of this type, the chip constituting the layer thickness regulating member is brought into contact with the developing roller to regulate the layer thickness of toner carried on the surface of the developing roller. The seal members are each disposed between the longitudinal end portion of the thin plate spring and an axial end portion of the developing roller, and therefore prevent leakage of toner from between the longitudinal end portion of the thin plate spring and the axial end portion of the developing roller.
In recent years, there is an increasing demand to reduce the number of parts constituting a developing device, in order to reduce a manufacturing cost of the developing device. So, such a layer thickness regulating member has been proposed, in which the free end portion of a thin plate spring is provided with no chip, and therefore is brought into direct contact with a developing roller to regulate the layer thickness of toner carried on the surface of the developing roller. This layer thickness regulating member will be referred to as “no-chip-mounted layer thickness regulating member”, hereinafter.